Preparation of supported Co catalysts from Co-Mg-Al layered double hydroxides for carbon dioxide reforming of methane

Mg(Al)O mixed oxide-supported Co catalysts were prepared by using Co-Mg-Al layered double hydroxides (LDHs) as precursors and their structural and catalytic properties for CH4-CO2 reforming were studied. Upon calcination and reduction, Co-Mg-Al LDHs were decomposed to Mg(Co, Al)O mixed oxides and gave rise to highly dispersed Co metal particles with the mean size of ∼9-10 nm. The catalytic activity, stability, and coke resistance of Co/MgAl increased with the increase of Co loading. The 12%-15%Co/Mg3Al catalysts showed high and stable activity as well as less coke deposition during 30 h of reaction at 1023 K. Sintering of Co particles was not clearly observed, indicative of good thermal stability of Co particles, and this could be attributed to the strong metal-support interaction between Co particles and Mg(Al)O. It was also found that the optimum LDHs-Co/MgAl catalyst exhibited superior coke resistance than the LDHs-Ni/MgAl catalyst. Particularly during 25 h of reaction at 873 K, the 12%Co/Mg3Al catalyst showed much higher catalytic stability and much less coke deposition as compared to the 12%Ni/Mg3Al catalyst, highlighting the great potential of using Co instead of Ni as an active catalyst for the CH4-CO2 reforming.